The increase in Internet traffic and emerging multimedia applications, such as video on demand, high definition Television (TV), video conference, and interactive online games requires an increase in bandwidth of access networks. To satisfy the increase in bandwidth and support such applications, Time Division Multiplexing (TDM) Passive Optical Networks (PONs), such as Gigabit PONs (GPONs) and Ethernet PONs (EPONs), are currently deployed worldwide to potentially serve millions of users. Traditionally, the maximum transmission distance of a PON is less than or about 20 Kilometers (km) and the splitting ratio is from about 1:16 to about 1:64, as defined in International Telecommunication Union (ITU) Telecommunication Standardization Sector (ITU-T) and Institute of Electrical and Electronics Engineers (IEEE) standards. The splitting ratio is the ratio of one central office equipment, e.g. an Optical Line Terminal (OLT), to a plurality of user equipments, e.g. Optical Network Terminals (ONTs).
Recently, there has been interest in long-reach and large splitting ratio PONs that have transmission distances larger than about 20 km and splitting ratios larger than about 1:64. In such long-reach and large splitting ratio PONs, the number of central offices, which can serve the same quantity of user terminals, can be substantially reduced. Additionally, the hierarchy of the PON can be simplified, the equipment and operation cost can be reduced, and the quality of service for real-time traffic (e.g. video on demand) can be improved due to the reduced number of hops in the system. Accordingly, ITU-T has defined a standard (ITU-T G.984.6) for GPONs with reach extension. In this standard, optical amplification and/or Optical-Electrical-Optical (OEO) regeneration are considered for long-reach PON implementations. Using optical amplifiers or optical regenerators, long-reach PONs having transmission distances up to about 100 km have been demonstrated. However, the optical amplifiers or generators are active equipment that can increase the cost and/or maintenance requirements in the system, which may be unattractive for large scale deployment. Achieving long-reach PONs without optical amplifiers or regenerators remains attractive but difficult.